Accumulated other comprehensive income (loss) - Changes in Accumulated OCI by Component and Reclassifications Out of Accumulated OCI (Details) $ in Millions	3 Months Ended
	May 04, 2019 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 1,201.6
Other comprehensive income (loss) (“OCI”) before reclassifications	(4.9)
Amounts reclassified from AOCI to net income	(0.2)
Total other comprehensive (loss) income	(5.1)
Ending Balance	1,161.4
Foreign currency translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(248.4)
Other comprehensive income (loss) (“OCI”) before reclassifications	(2.0)
Amounts reclassified from AOCI to net income	0.0
Total other comprehensive (loss) income	(2.0)
Ending Balance	(250.4)
Losses on available-for-sale securities, net
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(0.5)
Other comprehensive income (loss) (“OCI”) before reclassifications	0.3
Amounts reclassified from AOCI to net income	0.0
Total other comprehensive (loss) income	0.3
Ending Balance	(0.2)
Gains (losses) on cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	4.0
Other comprehensive income (loss) (“OCI”) before reclassifications	(3.2)
Amounts reclassified from AOCI to net income	(0.4)
Total other comprehensive (loss) income	(3.6)
Ending Balance	0.4
Accumulated other comprehensive loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(302.8)
Ending Balance	(307.9)
Pension Plan | Actuarial losses
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(53.8)
Other comprehensive income (loss) (“OCI”) before reclassifications	0.0
Amounts reclassified from AOCI to net income	0.2
Total other comprehensive (loss) income	0.2
Ending Balance	(53.6)
Pension Plan | Prior service credits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(4.1)
Other comprehensive income (loss) (“OCI”) before reclassifications	0.0
Amounts reclassified from AOCI to net income	0.0
Total other comprehensive (loss) income	0.0
Ending Balance	$ (4.1)